You cannot modify /usr/lib. Use /usr/local/lib instead.

You need to notarize your download. In your case, sign the app and put it into a DMG file. Then notarize the DMG.

You will have to ask the scipy developers about their code. I'm aware of community practices with regards to tools like conda. I don't think those practices work well in the Mac world. Quite frankly, I don't think they work well in the Linux world either. I've seen people go through an awful lot of trouble, and spend an awful lot of money, when they just didn't realize they were running buggy, out-of-date versions of libraries. WWDC is Monday. There is a good chance there will be a new version of Accelerate, along with everything else.

Internet tutorials are risky. If you have questions about specific instructions, it would be best to post a link to them. Generally speaking, you shouldn't be doing any of that. That is Swift code. You should parse the receipt information using something like node or Python on your server, as instructed here.

There is no "typical" backend. Firebase only seems popular because so many people have problems with it and post about it. 😄 I strongly encourage looking at AWS. They have many, many solutions available. Many of them are low-cost or even free initially.

Any public Apple API would work. The key part is what it is being used for. If you are showing it to the user for use inside your app, then Apple encourages this use. You just have to be careful with the part about "returning the translation to my own app for further processes". I'm not sure what you mean about sharing specific URLs. I think there is a restriction of non-Apple URLS. You can use them, you just have to use the official "link" tool and make sure that the text and URL are both the URL. That way people can easily see that the URL is a non-Apple site. But it is always better to share official Apple URLs anyway. 3rd party sites are often old and incorrect.

From what I understand, if you use an open-source cryptography library like OpenSSL in the App Store, you will need to get import compliance for the French App Store. This is in addition to the confusing export compliance from US-based Apple. The French form is not required if you use only methods provided by the operating system.

It looks like you are using the RMStore project from GitHub. It seems to depend on OpenSSL. Plus, it hasn't been updated in years. There might be legal problem too. The last time I checked, if you link your app to OpenSSL, you will need special authorization from France to sell in the French App Store.

Apple does not purposely curb performance on older hardware. The most likely explanation is some incompatible 3rd party software. Your memory usage is out of control. 7 GB for a text editor?

In the past, WWDC was in-person, so all of the labs were during the day. I can't say what will happen at WWDC this year. However, since the last WWDC, Apple has had many additional online support sessions at all hours and in all different languages. And in any event, getting up at 2am is kind of a WWDC tradition, if you wanted to see the keynote in person.

That is correct.

This is a difficult question to answer. On one hand, there are too many answers. On the other hand, you haven't provided enough information. Most of the available solutions assume that your listener always runs in the background and doesn't need a logged-in GUI session. If your listener can run in the background and doesn't need to be constantly logged in, then any solution you can find on the internet will work. That's just a basic network listener. Your only complication is that you will have to support HTTP. Your Mac already has a full-blown web-server built in. The easiest solution would be to just enable it and use it. From there, it is merely a question of how much extra cleverness and complexity you want to add. If you don't want to use the built-in web server, you will have to add your own code to respond to HTTP requests. Apple's APIs do support that. You will need to use launchd to start your server automatically. You can just start your server at boot up or you can use launchd cleverness to automatically launch your app in response to activity on the listening port. If you require a logged in user GUI session, then you will need a launchd agent to launch your app. I don't know if the other launchd cleverness will work in this case.

Both std::optional and std::enable_if_t work fine. You have to set the standard to C++17. There is no need to change the C++ library.

It is unlikely that anyone will post any information that might be a violation of Apple license agreements, developer terms, or developer forum rules. As Apple developers, we have to follow Apple's rules, both written and unwritten. We try to do good work and avoid getting caught up in some technicality that would cause Apple to shut down our business. Apple's relationship to the US government is much the same. As a global company, with deep ties to China, and little US military connections, Apple is in a precarious spot. This is just how it is right now.

Why would you need to purchase an SSD for a 2017 MacBook Pro? Doesn't it come with an SSD? It sounds like your computer is not functional.